Psychopaths use different people for different types of supply depending on what they're looking for. We are all just tools to them and you use different tools for different purposes. Hammers have a different function than wrenches, screwdrivers, pliers, and so on. Money is just one thing they will use you for, even if they have a lot of their own and don't need yours. If you don't have money, they will use you as a source of supply for other things:

1) Sexual outlet: perversions/fetishes/fantasies they secretly have, or just someone new and different besides the long-term supply.

2) Image management: trophy wife/husband they can 'wear' like arm candy and show off to their peers; or conversely, a 'wholesome' conservative partner who makes them look normal to their family and community (this is especially useful if they're hiding behind religion as part of their mask).

3) House Mouse: someone who cooks, cleans, takes care of everything (especially them), and raises the kids like an unpaid servant, maid, and nanny.

4) Networking: has lots of professional and/or social connections and clout that can boost their career, popularity, or give them access to more varied supply.

These are just a few of the things they use people for and not the only things. I think @shattered world described it well when she said they use supplies for different things like people use different types of clothing for different purposes. None are more valuable than the others, just more appropriate for the need. Needing a warm coat in winter, but "discarding" it for the summer.

Ultimately, what you need to know is that it's all about power and control for them in everything they do. All the time. That is the main motivating factor in everything that drives them to do what they do. The monster that did the horrific, heinous crimes to you, did those things out of a need to control and humiliate you so that they felt more powerful. It's a testament to what they are all about and nothing to do with you.

Oftentimes we wonder why the next target is more "their type". But the thing is, they don't have a type, despite how they may have described their perfect type to you. They all do this for the following reasons:

1) To lure you in and hook you by claiming YOUR assets/features are their perfect type and what they look for in a person (blonde, brunette, red-head; blue, brown, green eyes; tall, short, fat, thin; younger, older.... you name it). They will mirror you and describe whatever traits you have as their perfect partner.

OR

2) To make you feel inferior, insecure, jealous, and to groom you to be what their supposed (non-existent) perfect type is (using previous exes or future targets as an example). In this case, they will state everything that is the opposite of you to be their preference. If you're brunette, they'll say they like blondes and vice versa. Whatever you are like, they will proclaim they like something you are not.

The reality that you discover after surviving one of these monsters, is that anything with a pulse will suffice and even that's debatable. Each target is as different from all the others to be mind-boggling and prove there IS no type. Not even age or sex. They are equal opportunity lazy opportunists and only looking for their next best source of supply that requires the least amount of work for them with the biggest "return."